Cypripedium in China

Dr. Holger Perner is graduated as Diplom-Biologe (master degree in plant ecology) in 1991 and PhD (ecology) in 1996.
Until 2001 researcher and scientific editor in a German national research center.
Born in Hamburg, Germany, since 2001 working for the Huanglong Nature reserve, Sichuan, China.

Cypripedium yunnanense

ON: How long are you studying orchids and specially Cypripedium?
HP: My interest in orchids goes back to my childhood and the interest in slipper orchids aroused early. I was hooked to cypripediums when our neighbor, my schoolteacher, showed me a color painting of Cypripedium calceolus, native
to the mountains of central and southern Germany. I was about 8 years old at that time and it took me several years before I could see my first Cypripedium in flower in the wild. Oddly enough it was not in Europe but in Manitoba, Canada, where I was stationed for some weeks during my military service. Since 1984 I cultivate cypripediums, some ten years after I started to cultivate tropical orchids. Scientifically I study cypripediums since my days at the university. My interest in Orchids stretches over more than just the slipper orchids and I have a keen interest in genera like Pleione (another genus mostly at home in China), Cymbidium and Dendrobium , to mention just a few. But admittedly the slipper orchids are always top on my list ...

ON: How many species does this genus have?
HP: The genus comprises of 45 species.

ON: Which is its geographical distribution?
HP: Cypripediums are confined to the northern hemisphere where they mainly grow in the boreal regions as well as temperate mountain forests in Europe, Asia and North America. Few species occur in subtropical regions of northern
central America and southeast Tibet.

ON: Which is or are the most wide spread species?
HP: The most widespread species is Cypripedium guttatum, which can be found in northeastern Europe, northern Asia, southwest China, Japan and northwest North America. Cyp. calceolus is not occurring in North America and thus not a circumpolar species like Cyp. guttatum. The North American yellow slipper orchids only superficially resemble the Eurasian Cyp. calceolus by color and overall shape but have distinct morphological characters and belong to another species, Cyp. parviflorum, which comprises of 3 varieties.

ON: China seems to be one of the richest countries on species of Cypripedium, how many occur there?
HP: No other country in the world hosts so many slipper orchids than China does. 21 species of Paphiopedilum and 32 species of Cypripedium grow within its boundaries.

ON: Which are the Chinese endemic species?
HP: Endemic to China are 20 Cypripedium species: Cyp. subtropicum, Cyp. flavum, Cyp. henryi, Cyp. segawai, Cyp. fasciolatum, Cyp. farreri, Cyp. franchetii, Cyp. calcicolum, Cyp. yunnanense, Cyp. ludlowii, Cyp. palangshanense, Cyp. plectrochilum, Cyp. formosanum, Cyp. margaritaceum, Cyp. fargesii, Cyp. sichuanense, Cyp. lichiangense, Cyp. forrestii, Cyp. micranthum and Cyp. bardolphianum. Cyp. wardii is also known from Northern Burma and Cyp. lentiginosum from Southeast Yunnan most likely occurs also south of the border in northern Vietnam.

ON : Which are the characteristics of their habitat?
HP: Most Chinese cypripediums occur in open shrub and open woodland at altitudes between 2000 and 3600 m on limestone within a layer of friable soil with a mesic moisture regime. Few grow in more shady situations in dense shrub,
like Cyp. debile and Cyp. sichuanense. Cyp. tibeticum on the other hand can be often found in alpine meadows fully exposed to the sun. However, during the growing period in summer the monsoon often brings cloudy weather. And
it is also the climate in southwestern China, the home of 27 of the 32 Chinese species, that perhaps forms the most characteristic element in the set of growing conditions. During the main growing season in summer the weather
in the mountains is relatively cool, often overcast and rainfalls are frequent. Towards autumn it becomes sunnier and drier, often with slightly higher day temperatures but cooler nights. When the first severe frosts set in around
late September and early October the cypripediums shed their seeds and the leaves start to whither. Winter starts in November and is often sunny and usually rather dry and constantly cold. Warm-spells during winter are
almost unknown and snowfall only becomes more frequent towards the end of the
winter in March.

ON: In your lecture, you said that the interest in cultivating this genus has been increasing in the last decade. All of them should be cultivated under temperate conditions?
HP: Yes. The few warm-temperate to subtropical species from Mexico to Guatemala are nearly impossible to be kept alive in cultivation and Cyp. subtropicum from southeastern Tibet has never been tried in cultivation. All other
species are temperate to cool-temperate species. With some tricks, however, they can be grown even in warmer regions. One is to grow them under lights in pots filled with an inert mix of clay pebbles, pumice perlite and
perhaps a little fine bark or shredded tree fern (80-90 % mineral and 10-20 % organic compounds) in an air-conditioned room with day temperatures around 20 °C and a night drop of 5 °C or so. The relation humidity should lie around 70 %. Towards the end of the growing season (some 5-6 month after emerging of the leaves) the day temperature should be as low as 10-15 °C and with the leaves dropping the plants can be put into hibernation (within their pots) by placing them in a fridge at constant lows around 4 °C. They shouldn't have temperatures above 8 °C for at least 8-12 weeks and shouldn't freeze either. In Japan I saw a successful cypripedium culture in a suburban of Tokyo. It was July, the temperature rarely fell below 30 °C even at night and the humidity was very high. Still several types of cypripediums (species from Eastern Asia like Cyp. macranthos as well as North American species and
several horticultural hybrids) were thriving in none-glazed ceramic pots filled with a substrate consisting mainly of coir (shredded coconut hulls and cut fibers) with a little fine charcoal added. The moisture evaporating through the pot's walls kept the roots cool enough to grow. While the mentioned types of cypripediums looked healthy and happy, the few species from Southwest China I saw in Tokyo weren't doing well. They seem to prefer overall cooler growing conditions which can easily be match with in higher regions in the mountain areas of Japan, in most of Europe and North America and certainly also in cooler regions in the southern hemisphere.

ON: Is it very hard to cultivate them? What kind of care the grower should give?
HP: Under temperate conditions cultivating cypripediums is not too difficult. In China I work with a mix often used by North American growers too: Perlite with some organic matter added. The composition is 80-90 % Perlite, the
rest turf soil from alpine meadows which is not unlike peat moss with a little soil, i.e. clay particles added; this turf soil is commonly sold in Sichuan as potting material for all kinds of plants. As it is rather acidic, pH 3.5 to 4, I add a little calcium hydroxide powder to neutralize the humic acids in the turf soil and mix it subsequently with the perlite. I water with regular tap water and fertilize every other week with a quarter strength all purpose fertilizer (NPK 20:20:20 with trace elements) during the growing season. During the dormant season in winter, when the growth above soil
has died down and the cypripediums are hibernating as rhizomes with fully intact root system and underground buds for the next years growth (thus they have to be left undisturbed in the pot!) the substrate has to be kept just slightly moist but never wet and the temperature should never be higher than 8 to 10 °C for at least three months. Generally slugs and snails are the most important pest on cypripediums of which the grower has to take care of.

ON: How many species and genera of orchids occur in China?
HP: China has about 1300 orchid species in approx. 180 genera and several species and some genera are endemic, like e.g. Changnienia amoena or Nothodoritis zhejiangensis.

ON: Thank you, Dr. Holger Perner.

Cypripedium bardolphianum

Cypripedium fasciolatum

Cypripedium flavum and tibeticum

Cypripedium henryi

Cypripedium micranthum

Cypripedium palangshanense

Cypripedium sichuanense

Photos by H.Perner

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